Answer:
I'm not completely sure on this. There was a variety of factors, but I think your best answer here would be "ASL being simplified and making it easier to learn and teach." However, the answer could also be "A change in social climate that was more accepting of differences in people."
During the time, there was a slight shift in social acceptance, but it would, in my mind, make more sense for the other choice to be true, I only hesitate on this because there were slight developments in spelling ASL that allowed easier teacher, child, and parent communication through the use of spelling in sign, though ASL itself did not undergo major reconstruction, but rather had additions made to it.
